This invention relates to calculators capable of repetitively performing selected mathematical computations, and more particularly, portable, pocket-type calculators for automatically performing selected mathematical computations repetitively and at predetermined intervals.
Calculators for performing the arithmatic computations of addition, subtraction, multiplication and division have become quite popular in all types of applications. With the advent of portable, battery-operated, pocket-type calculators, a substantial number of people have elected to perform arithmatic computations by use of such devices rather than manually. Even grade school children are employing portable, pocket-type calculators for performing their mathematical computations once they learn the fundamentals of mathematics.
In addition to being widely used by diverse segments of our society, such calculators are used for every conceivable computational function. Certain types of calculators can perform the basic arithmatic computations of addition, subtraction, multiplication or division repetitively. That is, the same number can be added to a base quantity repetitively in order to continuously accumulate a new total.
Certain types of activity require that a specified quantity be determined, generally by some type of arithmatic computation, and then that quantity must be added, subtracted, multiplied or divided by a specific time period in order to obtain a total quantity that is a function of the specified time period. One example of such a requirement would be in an automobile rally. In a rally, the average speed per second necessary to complete the course in the specified time is first determined, then that average speed is multiplied by the elapsed time in seconds to determine whether the participant is on time while driving the course.
Pocket type portable calculators have been employed to ascertain the average speed and then to multiply that average speed by the total number of seconds elapsed. However, determination of the elapsed time is done by reference to a stop watch or other such device so that the calculations are made at selected intervals rather than on a continuous basis. Additionally, the slight error in timing due to the necessity of transferring the time from the watch to the calculator can result in an error sufficient to cause loss of the race.
In business meetings with a number of people present it may be desirable to determine the cost of the meeting in terms of the salaries of the participants and the meeting elapsed time. This can be ascertained by first determining the cost per second of each participant's time, adding all of the costs per second together and multiplying this total by the total meeting elapsed time in seconds. Again, in the interest of maintaining costs and expenses at a minimum, it may be desirable and advantageous to be able to ascertain these costs on a second by second basis as the meeting progresses in order to facilitate termination of the meeting when the meeting expense becomes greater than the value of the meeting, or when the expense exceeds some predetermined amount. SUMMARY OF THE INVENTION
In practicing this invention, there is provided a calculator adapted to perform selected mathematical computations such as, for example, addition, subtraction, multiplication and division, and to display the total produced by the selected mathematical computations. The calculator includes a clock circuit which can be selectively operated to repetitively perform any selected mathematical computation at predetermined time intervals allowing a display of the total obtained by repetitive performance of the mathematical computation for the specified time period.